In recent years, an imaging apparatus such as a digital still camera that images a subject such as a person to generate captured images and records the generated captured images has been popularized. Moreover, an imaging apparatus having an autofocus (AF) function of automatically performing focus adjustment during imaging in order to make a user's shooting operation easy has been widely used as the imaging apparatus.
As an example of such an imaging apparatus, an imaging apparatus in which light having passed through an imaging lens is pupil-split to form a pair of images, and the position of the imaging lens is determined by measuring the distance between the two formed images (detecting a phase difference) has been proposed. For example, an imaging apparatus in which pixels (phase-difference detection pixels) for phase-difference detection (focus detection) for performing pupil splitting by blocking the half of subject light received by a light receiving element and pixels (image generation pixels) for generating captured images are provided in an imaging device has been proposed. When performing phase-difference detection, the imaging apparatus forms a pair of images from the signals of the phase-difference detection pixels and measures the distance between the two formed images to thereby calculate the amount of focus shift. Subsequently, the imaging apparatus calculates a displacement of the imaging lens based on the calculated amount of focus shift and adjusts the position of the imaging lens based on the calculated displacement to thereby achieve focusing (focus adjustment).
In order to perform phase-difference detection and image generation with high precision, an imaging apparatus in which the focusing position in the phase-difference detection pixel is different from the focusing position in the image generation pixel has been proposed (for example, see FIG. 8 of JP-A-2009-109965). In the imaging apparatus, a microlens provided in the phase-difference detection pixel has different characteristics from the characteristics of a microlens provided in the image generation pixel by changing a lens thickness, a lens diameter, or a lens material. Alternatively, in the imaging apparatus, the distance between the microlens and the light receiving element in the phase-difference detection pixel is different from the distance between the microlens and the light receiving element in the image generation pixel.